Radio frequency switch device
By employing multiple stacked transistors and high-isolation branches in the RF switch design, the isolation and switching time issues of RF switches in high-power capacity demand scenarios are solved, achieving efficient RF signal control and power capacity improvement.
Patent Information
- Application Number
- CN202512024421.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-30
- Publication Date
- 2026-03-03
AI Technical Summary
Existing RF switches struggle to effectively improve power capacity and isolation in high-power capacity demand scenarios, especially under high-power signal conditions, where they suffer from long switching times and insufficient isolation.
The main signal path is composed of multiple stacked transistors and controlled by transistors with gate-source bias structure. It combines high isolation branches and parallel absorption branches, and uses reverse voltage to control the switching state, thereby improving the voltage withstand capability of the transistors and the accuracy of the control voltage.
It improves the power capacity and isolation of RF switches, reduces switching time, enhances the control capability of RF signals, and is suitable for safe switching of high-power signals.
Smart Images
Figure CN121602971A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of radio frequency integrated circuit technology, and in particular to a radio frequency switching device. Background Technology
[0002] Radio frequency (RF) switches are important RF electronic devices used to control the on / off state and path selection of RF signals. They are mainly used in front-end modules such as transceiver units, phase shifters, and phased arrays, as well as various control circuits. A good RF switch features wide bandwidth, low insertion loss, high isolation, high power capacity, and high switching speed.
[0003] High-power RF switches can control the safe, reliable, and efficient switching of high-power RF signals between different paths. With the increase in wireless communication speed and the increasing complexity and sophistication of application scenarios, the demand for high-performance RF switches is also increasing, especially in terms of power capacity. In some high-power capacity scenarios, such as when the RF input signal power is large, the role of high-power capacity switches is very important.
[0004] Therefore, there is an urgent need for a radio frequency switch with increased power capacity to meet the needs of high power capacity scenarios. Summary of the Invention
[0005] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a radio frequency switching device that can effectively improve power capacity to meet the needs of high power capacity scenarios.
[0006] This invention is implemented according to the following scheme: A radio frequency switching device is provided, comprising: a signal input module and two symmetrical signal paths with identical circuit structures, wherein the signal input module is connected to the signal paths; The signal path includes: a series signal main path, a high isolation branch, a parallel absorption branch, and an output main path; the series signal main path is connected to the signal input module, the high isolation branch, the parallel absorption branch, and the output main path; the signal path is connected to a first voltage and a second voltage, the second voltage being the reverse voltage of the first voltage; the first voltage and the second voltage are used to control the switching state of the signal path. The serial signal main path includes multiple stacked transistors, which are gate-source dual-biased structures; the radio frequency signal is transmitted sequentially through the signal input module, the signal path in the on state, and the output main path; the leaked radio frequency signal is fed to ground through the signal path in the off state.
[0007] Compared with the prior art, the beneficial effects of the radio frequency switching device of the present invention are as follows: through the series signal main path composed of multiple stacked transistors, the input and output terminals of the radio frequency signal can improve the end-to-end turn-off degree due to the voltage sharing of each transistor, thereby improving the power capacity; at the same time, through the gate-source biased transistor, the control voltage on the transistor is improved, and the switching time is reduced.
[0008] Optionally, it also includes a bias module, which includes a switching transistor and a power supply voltage. The gate of the switching transistor is connected to the first voltage, and the drain of the switching transistor is connected to the power supply voltage and the second voltage.
[0009] Optionally, the signal input module includes a first capacitor and a first inductor, wherein the first inductor is connected to the first capacitor and the series signal main circuit.
[0010] Optionally, the main output circuit includes a second capacitor and a second inductor, wherein the second inductor is connected to the second capacitor and the series signal main circuit.
[0011] Optionally, the series signal main path includes N series-connected first transistors, N first gate resistors, and N first source resistors. The first gate resistors are connected to the gate of the first transistors and a first voltage, and the first source resistors are connected to the source of the first transistors and a second voltage. The drain of the first transistor is connected to the signal input module, and the source of the Nth transistor is connected to the parallel absorption branch and the output main circuit. When N is odd, the drain of the (N+1) / 2th first transistor is connected to the high isolation branch; when N is even, the source of the N / 2th first transistor is connected to the high isolation branch.
[0012] Optionally, when N is an odd number, the high isolation branch includes (N-1) / 2 second transistors connected in series, (N-1) / 2 second gate resistors, (N-1) / 2 second source resistors, and a third capacitor; The second gate resistor is connected to the gate of the second transistor and the second voltage, and the second source resistor is connected to the source of the second transistor and the first voltage. The drain of the first second transistor is connected to the drain of the (N+1) / 2th first transistor, and the source of the (N-1) / 2nd second transistor is grounded through the third capacitor.
[0013] Optionally, the parallel absorption branch includes (N+1) / 2 third transistors connected in series, (N+1) / 2 third gate resistors, (N+1) / 2 third source resistors, and a matching network; The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N+1) / 2th third transistor is grounded through the matching network.
[0014] Optionally, when N is an even number, the high isolation branch includes N / 2 second transistors connected in series, N / 2 second gate resistors, N / 2 second source resistors, and a third capacitor; The second gate resistor is connected to the gate of the second transistor and the second voltage, and the second source resistor is connected to the source of the second transistor and the first voltage. The drain of the first second transistor is connected to the drain of the N / 2th first transistor, and the source of the N / 2th second transistor is grounded through the third capacitor.
[0015] Optionally, the parallel absorption branch includes (N / 2)+1 third transistors connected in series, (N / 2)+1 third gate resistors, (N / 2)+1 third source resistors, and a matching network; The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N / 2)+1th third transistor is grounded through the matching network.
[0016] Optionally, the matching network includes a fourth capacitor, a third inductor, and a first resistor, and the source of the third transistor is grounded sequentially through the fourth capacitor, the third inductor, and the first resistor. Attached Figure Description
[0017] Figure 1 This is a circuit diagram of the radio frequency switching device of the present invention; Figure 2 This is a circuit diagram of the bias module of the present invention; Figure 3 This is a circuit diagram of a single signal path when N is an odd number in this invention; Figure 4 This is a circuit diagram of a single signal path when N is an even number in this invention; Figure 5 This is a circuit diagram of the signal path when N is 4 in this invention; Figure 6 This is a schematic diagram of the simulation results when the high isolation branch of the present invention is connected to different positions of the serial signal main path; Figure 7A schematic diagram of the simulation results before and after introducing the high isolation branch of this invention; Figure 8 This is a schematic diagram of the simulation results of the input power of the radio frequency switching device of the present invention at different compression points; The attached diagram shows the following labels: 1. Signal input module; 2. Signal path; 201. Series signal main path; 202. High isolation branch; 203. Parallel absorption branch; 204. Output main path. Detailed Implementation
[0018] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.
[0019] In the following description, when referring to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims. In the description of this application, it should be understood that the terms "first," "second," "third," etc., are used only to distinguish similar objects and are not necessarily used to describe a specific order or sequence, nor should they be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0020] See Figure 1 As shown, a radio frequency switching device of the present invention includes: a signal input module 1 and two symmetrical signal paths 2 with identical circuit structures, the signal input module 1 being connected to the signal path 2; each signal path 2 includes: a series signal main path 201, a high isolation branch 202, a parallel absorption branch 203, and an output main path 204; the series signal main path 201 is connected to the signal input module 1, the high isolation branch 202, the parallel absorption branch 203, and the output main path 204; the signal path 2 is connected to a first voltage and a second voltage, the second voltage being the reverse voltage of the first voltage; the first voltage and the second voltage are used to control the switching state of the signal path 2; the control logic of the first voltage on the series signal main path 201 is opposite to the control logic of the first voltage on the high isolation branch 202 and the parallel absorption branch 203; The series signal main path 201 includes multiple stacked transistors, which are gate-source dual-biased structures. The radio frequency (RF) signal is transmitted sequentially through the signal input module 1, the signal path 2 (in the on state), and the output main path 204. Leaked RF signals are fed to ground through the signal path 2 (in the off state). Specifically, the RF signal enters the signal input module 1 through the RFIN port. Through the series signal main path 201 composed of multiple stacked transistors, the input and output terminals of the RF signal can improve the end-to-end turn-off degree due to the voltage sharing of each transistor, thereby increasing the power capacity. At the same time, through the gate-source biased structure of the transistors, the control voltage's control over the transistors is improved, and the switching time is reduced.
[0021] See Figure 2 As shown, in one embodiment of the present invention, the radio frequency switching device further includes a bias module. The bias module includes a switching transistor SW1 and a supply voltage VDD. The gate of the switching transistor SW1 is connected to a first voltage V1, and the drain of the switching transistor SW1 is connected to the supply voltage VDD and a second voltage V2. When the first voltage V1 is high, the switching transistor SW1 is turned on, and the second voltage V2 is connected in series to ground and is at a low level. When the first voltage V1 is low, the switching transistor SW1 is turned off, and the second voltage is at a high level provided by the supply voltage VDD. Through the bias module, the value of the second voltage V2 is determined by the first voltage V1, thereby reducing one control voltage and achieving the effect of controlling two radio frequency switching signal paths 2 with a single positive voltage, thus improving control convenience.
[0022] In this invention, all transistors are enhancement-mode pHEMT transistors. The increase in gate voltage weakens the depletion effect of the two-dimensional electron gas channel in the gallium arsenide process enhancement-mode transistor, thereby increasing the saturation leakage current of the transistor and thus improving the power capacity. The increase in gate voltage increases the switching compression point by 1dB, which is equivalent to increasing the power capacity of the switch. In order to reduce the risk of transistor breakdown, the power supply voltage VDD of this invention is 5V.
[0023] In one embodiment of the present invention, the signal input module 1 includes a first capacitor C1 and a first inductor L1. The first inductor L1 is connected to the first capacitor C1 and the series signal main circuit 201. The output main circuit 204 includes a second capacitor C2 / C2' and a second inductor L2 / L2'. The second inductor is connected to the second capacitor and the series signal main circuit 201.
[0024] In one embodiment of the present invention, the first voltage and the second voltage are opposite voltages to each other, so as to Figure 1For example, in one of the signal paths 2, the first voltage is connected to the gate of the transistor in the main series signal path 201, the source of the transistor in the high isolation branch 202, and the source of the transistor in the parallel absorption branch 203; the second voltage is connected to the source of the transistor in the main series signal path 201, the gate of the transistor in the high isolation branch 202, and the gate of the transistor in the parallel absorption branch 203 (corresponding to...). Figure 1 In the signal path 2 on the right, the first voltage is connected to the source of the transistor in the main series signal path 201, the gate of the transistor in the high isolation branch 202, and the gate of the transistor in the parallel absorption branch 203. The second voltage is connected to the gate of the transistor in the main series signal path 201, the source of the transistor in the high isolation branch 202, and the source of the transistor in the parallel absorption branch 203 (corresponding to...). Figure 1 The left-hand signal path 2 is used to enable the switching state of both signal paths 2 to be controlled by only the first voltage and bias module, thereby improving the control voltage's control over the transistor and reducing the switching time.
[0025] In one embodiment of the present invention, the series signal main path 201 includes N series-connected first transistors M11-M1N / M11'-M1N', N first gate resistors RG1 / RG1', and N first source resistors RS1 / RS1'. The multiple first transistors are stacked, and the first transistors are gate-source dual-biased structures, and the value of N is greater than or equal to 3. The first gate resistors are connected to the gate of the first transistors and the first voltage V1, and the first source resistors are connected to the source of the first transistors and the second voltage V2. The drain of the first first transistor is connected to the signal input module 1, and the source of the Nth first transistor is connected to the parallel absorption branch 203 and the output main path 204.
[0026] See Figure 3 The diagram shows a circuit diagram of a single signal path 2 when N is odd. When N is odd, the drain of the (N+1) / 2th first transistor is connected to the high-isolation branch 202. See [link to diagram]. Figure 4 As shown, the circuit diagram of signal path 2 is shown when N is even. When N is even, the source of the N / 2th first transistor is connected to the high isolation branch 202.
[0027] See Figure 3As shown, in one embodiment of the present invention, when N is odd, the high isolation branch 202 includes (N-1) / 2 second transistors M21-M2a connected in series, (N-1) / 2 second gate resistors RG2, (N-1) / 2 second source resistors RS2, and a third capacitor C3. The multiple second transistors are stacked, and the second transistors are gate-source dual-biased structures. The second gate resistors are connected to the gate and second voltage of the second transistors, and the second source resistors are connected to the source and first voltage of the second transistors. The drain of the first second transistor is connected to the drain of the (N+1) / 2th first transistor, and the source of the (N-1) / 2nd second transistor is grounded through the third capacitor. Specifically, Figure 3 The value of a in the second transistor M2a is (N-1) / 2 to ensure that the high isolation branch 202 is located at the center of the serial signal main path 201, thereby improving the isolation.
[0028] The parallel absorption branch 203 includes (N+1) / 2 third transistors M31-M3r connected in series, (N+1) / 2 third gate resistors RG3, (N+1) / 2 third source resistors RS3, and a matching network. The multiple third transistors are stacked and have a gate-source dual-bias structure. The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N+1) / 2th third transistor is grounded through the matching network. Specifically, the value of r for the third transistor M3r is (N+1) / 2.
[0029] See Figure 4 As shown, in one embodiment of the present invention, when N is even, the high isolation branch 202 includes N / 2 second transistors M21-M2a connected in series, N / 2 second gate resistors RG2, N / 2 second source resistors RS2, and a third capacitor C3. The multiple second transistors are stacked, and the second transistors are gate-source dual-biased structures. The second gate resistors are connected to the gate and second voltage of the second transistors, and the second source resistors are connected to the source and first voltage of the second transistors. The drain of the first second transistor is connected to the drain of the N / 2th first transistor, and the source of the N / 2th second transistor is grounded through the third capacitor. Specifically, Figure 3 The value of 'a' in the second transistor M2a is N / 2 to ensure that the high isolation branch 202 is located at the center of the serial signal main path 201, thereby improving the isolation.
[0030] The parallel absorption branch 203 includes (N / 2)+1 third transistors M31-M3r connected in series, (N / 2)+1 third gate resistors RG3, (N / 2)+1 third source resistors RS3, and a matching network. The multiple third transistors are stacked and have a gate-source dual-bias structure. The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N / 2)+1th third transistor is grounded through the matching network. Specifically, the value of r for the third transistor M3r is (N / 2)+1.
[0031] See Figure 5 The figure shows a partial circuit structure of the RF switching device when N is 4. Positions a, b, c, d, and e in the figure represent different connection positions of the series signal main path 201. Figure 6 The diagram shows the isolation levels when the high isolation branch 202 is connected to positions a, b, c, d, and e, respectively. As can be seen from the diagram, the isolation level is highest when the high isolation branch 202 is connected to position c of the main series signal path 201. Therefore, in this invention, the high isolation branch 202 is connected to the first transistor located in the middle of the main series signal path 201 to maximize the isolation of the RF switching device.
[0032] In one embodiment of the present invention, the first capacitor C1, the second capacitor C2 / C2' and the third capacitor C3 / C3' are DC blocking capacitors used to isolate DC signals, and the first inductor and the second inductor L2 / L2' are fitted inductors on the bonding wire with an inductance of about 1nH, used to adjust the standing wave ratio between the input port RFIN and the output port RFout / RFout'.
[0033] In one embodiment of the present invention, the matching network includes a fourth capacitor C4 / C4', a third inductor L3 / L3', and a first resistor R1 / R1'. The source of the third transistor is grounded sequentially through the fourth capacitor, the third inductor, and the first resistor. When the matching network is in the open state of its signal path 2, the fourth capacitor is used to isolate the DC signal, preventing the DC shunt of the high-power signal from being fed to the bottom, thus ensuring the high-power design of the RF switching device. When the matching network is in the closed state of its signal path 2, the third capacitor and the fourth capacitor are in a low-impedance state in series resonance in the LS operating frequency band. When the series signal main path 201 is closed and the parallel absorption main path is open, the output port forms a ground loop with the parallel absorption branch 203 through the first resistor. By adjusting the resistance value of the first resistor to match the impedance characteristics of the parallel absorption branch 203, the output port presents a good matching state, effectively reducing the voltage standing wave ratio of the RF switching device in the closed state.
[0034] by Figure 1 For example, when the first voltage V1 is high and the second voltage V2 is low, the series signal main path 201 in the right signal path 2 is in the open state, and the high isolation branch 202 and the parallel absorption branch 203 are in the closed state; the series signal main path 201 in the left signal path 2 is in the closed state, and the high isolation branch 202 and the parallel absorption branch 203 are in the open state. The flow of the radio frequency signal is as follows: after entering the signal input module 1 through the input port RFIIN, the radio frequency signal passes through the serial signal main path 201 and the output main path 204 in the right signal path 2 in sequence to the output port RFout; the leaked radio frequency signal is fed to the ground through the high isolation branch 202 and the parallel absorption branch 203 in the left signal path 2.
[0035] When the first voltage V1 is low and the second voltage V2 is high, the series signal main path 201 in the right signal path 2 is closed, and the high isolation branch 202 and the parallel absorption branch 203 are open; the series signal main path 201 in the left signal path 2 is open, and the high isolation branch 202 and the parallel absorption branch 203 are closed. The flow of the radio frequency signal is as follows: after entering the signal input module 1 through the input port RFIIN, the radio frequency signal passes through the serial signal main path 201 and the output main path 204 in the left signal path 2 in sequence to the output port RFout'; the leaked radio frequency signal is fed to the ground through the high isolation branch 202 and the parallel absorption branch 203 in the right signal path 2.
[0036] When designing high-power RF switching devices, it is often necessary to increase the size of the transistors to handle greater RF signal power, due to isolation requirements. ,in =50Ω, For transistor turn-off capacitor, For angular frequency, transistor size and transistor turn-off capacitance Directly proportional to transistor size, isolation is inversely proportional to transistor size; that is, while increasing transistor size to improve power capacity, the isolation of RF switching devices deteriorates. See also... Figure 7 As shown, simulation results of isolation before and after introducing the high-isolation branch 202 are illustrated. The blue line represents the simulation results without the high-isolation branch 202 of this invention, and the red line represents the simulation results with the high-isolation branch 202 of this invention. Compared to the simulation without the high-isolation branch 202, the isolation is significantly improved by 20-25 dB. (See also...) Figure 8 The figure shows the simulation results of the input power of the RF switching device at different compression points. When the RF switching device is at the 1dB compression point, its corresponding input power P 1dBReaching 39.3dBm, meaning its power capacity can also reach 39.3dBm, from Figure 7-8 It is known that the isolation of the radio frequency switching device of the present invention can reach 55dB and can cover the 1~3GHz frequency band.
[0037] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A radio frequency switching device, characterized in that, include: A signal input module and two symmetrical signal paths with identical circuit structures, wherein the signal input module is connected to the signal paths; The signal path includes: a series signal main path, a high isolation branch, a parallel absorption branch, and an output main path; the series signal main path is connected to the signal input module, the high isolation branch, the parallel absorption branch, and the output main path; the signal path is connected to a first voltage and a second voltage, the second voltage being the reverse voltage of the first voltage; the first voltage and the second voltage are used to control the switching state of the signal path. The serial signal main path includes multiple stacked transistors, which are gate-source dual-biased structures; the radio frequency signal is transmitted sequentially through the signal input module, the signal path in the on state, and the output main path; the leaked radio frequency signal is fed to ground through the signal path in the off state.
2. The radio frequency switching device according to claim 1, characterized in that, It also includes a bias module, which includes a switching transistor and a power supply voltage. The gate of the switching transistor is connected to the first voltage, and the drain of the switching transistor is connected to the power supply voltage and the second voltage.
3. The radio frequency switching device according to claim 1, characterized in that, The signal input module includes a first capacitor and a first inductor, and the first inductor is connected to the first capacitor and the series signal main circuit.
4. The radio frequency switching device according to claim 1, characterized in that, The main output circuit includes a second capacitor and a second inductor, with the second inductor connected to the second capacitor and the series signal main circuit.
5. The radio frequency switching device according to claim 1, characterized in that, The series signal main path includes N series-connected first transistors, N first gate resistors and N first source resistors. The first gate resistors are connected to the gate of the first transistors and a first voltage, and the first source resistors are connected to the source of the first transistors and a second voltage. The drain of the first transistor is connected to the signal input module, and the source of the Nth transistor is connected to the parallel absorption branch and the output main circuit. When N is odd, the drain of the (N+1) / 2th first transistor is connected to the high isolation branch; when N is even, the source of the N / 2th first transistor is connected to the high isolation branch.
6. The radio frequency switching device according to claim 5, characterized in that, When N is an odd number, the high isolation branch includes (N-1) / 2 second transistors connected in series, (N-1) / 2 second gate resistors, (N-1) / 2 second source resistors, and a third capacitor; The second gate resistor is connected to the gate of the second transistor and the second voltage, and the second source resistor is connected to the source of the second transistor and the first voltage. The drain of the first second transistor is connected to the drain of the (N+1) / 2th first transistor, and the source of the (N-1) / 2nd second transistor is grounded through the third capacitor.
7. The radio frequency switching device according to claim 6, characterized in that, The parallel absorption branch includes (N+1) / 2 third transistors connected in series, (N+1) / 2 third gate resistors, (N+1) / 2 third source resistors, and a matching network; The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N+1) / 2th third transistor is grounded through the matching network.
8. The radio frequency switching device according to claim 5, characterized in that, When N is even, the high isolation branch includes N / 2 second transistors connected in series, N / 2 second gate resistors, N / 2 second source resistors, and a third capacitor; The second gate resistor is connected to the gate of the second transistor and the second voltage, and the second source resistor is connected to the source of the second transistor and the first voltage. The drain of the first second transistor is connected to the drain of the N / 2th first transistor, and the source of the N / 2th second transistor is grounded through the third capacitor.
9. A radio frequency switching device according to claim 8, characterized in that, The parallel absorption branch includes (N / 2)+1 third transistors connected in series, (N / 2)+1 third gate resistors, (N / 2)+1 third source resistors, and a matching network; The third gate resistor is connected to the gate of the third transistor and the second voltage, and the third source resistor is connected to the source of the third transistor and the first voltage. The drain of the first third transistor is connected to the source of the Nth first transistor, and the source of the (N / 2)+1th third transistor is grounded through the matching network.
10. A radio frequency switching device according to claim 7 or 9, characterized in that, The matching network includes a fourth capacitor, a third inductor, and a first resistor. The source of the third transistor is grounded through the fourth capacitor, the third inductor, and the first resistor in sequence.